Wearable Article With Highly Extensible Fastening Member Having Stress Distribution Features

ABSTRACT

Wearable disposable absorbent articles such as disposable diapers, having elastically extensible fastening members (also sometimes known as fastening “ears”) with particular features, extending from a chassis or main portion of the articles, are disclosed. The fastening members may be highly extensible and have an overall geometry characterized by greater length nearer the chassis or main portion and lesser length nearer the distal end. Examples disclosed may have a fastener zone having a Stiffness of at least about 1,500 N/m, and shape and dimensional characteristics, that help avoid problems of buckling and/or flipping of edges of the fastening members, dishing of fastener components, and fastening member tearing, while the articles are applied and worn.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/175,185, filed May 4, 2009, which is hereby incorporated by referencein its entirety.

FIELD OF THE INVENTION

The present disclosure generally relates to wearable disposableabsorbent articles such as disposable diapers, and more particularly, tofastening members (also known as fastening ears) as components orfeatures thereof.

BACKGROUND OF THE INVENTION

Some wearable articles are manufactured to include fastening members.For example, some varieties of diapers are manufactured with a pair ofoppositely-oriented side fastening members, extending laterally fromeach side of a first waist region of the chassis, each fastening memberhaving a fastener located at or near the outboard end thereof, andadapted to attach or adhere to a fastener receiving zone (“landingzone”) disposed on a second waist region of the chassis. The fasteningmembers may be formed in part or in whole of a nonwoven web material. Insome examples, the fastening members are formed at least in part of alaminate of one or more layers of nonwoven web material and one or morelayers or strands of a polymeric elastic material, and fashioned andadapted in such a way as to be elastically extensible in at least thedirection in which the fastening member is to be pulled duringapplication and use. One type has fastening members extending from therear waist region of the diaper, and is intended to enable the personapplying the diaper (hereinafter, “applier”) to lay the diaper open on asurface, with the rear region of the diaper beneath a reclining wearer'sbottom, wrap the chassis forward between the wearer's legs and up overthe front of the lower torso, draw each fastening member from the rearwaist region around a hip, and attach the end of each fastening memberto the front region via the fastener, thereby forming a waistband andpant-like structure about the wearer. When the diaper is applied, eachfastening member may be in direct contact with the wearer's skin at ahip.

In some examples of diapers having fastening members, it may bedesirable that the fastening members be formed so as to coversubstantial areas of skin at the wearer's hips. This may have twopurposes, among others: First, comfort, resulting from distribution ofnormal force components of tension forces in the fastening members overgreater, rather than lesser, areas of skin; and second, appearance.

It also may be desirable to form fastening members from material that isrelatively soft to the touch, pliable and stretchy. Purposes for thismay include comfort.

Fastening members may be subject to varying forces, resulting fromtugging during application, and from the wearer's movements at the hips,particularly if the diaper is snugly applied. These forces may havevarious undesirable effects. A typical fastening member, e.g., one thatextends from the rear waist region of a diaper, is longer at its inboardend than at its outboard end. This general geometry may be incorporatedto allow for, e.g., better fit about the wearer's hips, and betterdistribution of lateral tension forces along a greater length along thelocation(s) where the fastening member joins the rear waist region,thereby reducing the likelihood of tearing along that line or locationsproximate the inboard end of the fastening member. Conversely, arelatively shorter outboard end, typically having a fastener attachedproximate thereto, allows for tugging by the applier by simply graspingbetween thumb and forefinger, and for easy selection and placement of apoint or region of fastening, by simply placing the grasped, shortenedoutboard end at the desired location. This general geometry results inlateral tension forces being focused from a longer inboard region to ashorter outboard end region of the fastening member. This focusing,together with stretching, creates longitudinal force components withinthe fastening member.

Longitudinal force components acting within the fastening member maycreate the likelihood that portions of the fastening member such as apanel region and/or extensible zone thereof will undesirably laterallybuckle and/or flip away from the wearer. For purposes of maximizing skincoverage for best appearance, evenly distributing forces, and wearercomfort, panel regions of fastening members may be formed so as to havethe greatest length (in a longitudinal direction along the chassis)feasible under the circumstances. Increasing length adds to the area ofthe material forming the panel region. With increasing length andsurface area of the panel region, undesirable buckling/flipping of thepanel region material proximate either the top or bottom edges may bemore likely, particularly when the wearer bends at the hips. Thisproblem may be more likely to manifest itself in “tape” type fasteningmembers, in which a comparatively short tab member, bearing a fastenerand forming the end region of the fastening member, joins a relativelylonger side panel region, such that a step-wise decrease in length ofthe fastening member exists where the panel region ends and the tabmember extends therefrom. When the panel region and/or an extensiblezone thereof is highly extensible (and relatively pliable), it may tendto buckle and flip about the relatively short tab member.

In examples in which a layer forming an end region of a fastening memberis coextensive in length, or longer than, a layer of material formingthe region immediately inboard of the end region, buckling/flipping ofthe panel region proximate its edges may be less likely becauselongitudinal force components resulting from lateral tension in thefastening member may be distributed into the end region. As a result,however, such longitudinal force components may act at or about thelateral edges of the fastener and contribute to causing the fastener tobend or “dish”, i.e., contribute to causing its lateral edges to beurged to turn up and away from the surface to which it is attached. Forexample, one type of diaper fastening member may include a fastenerconsisting of a patch of hooks, a component of a hook-and-loop fasteningsystem (such as a 3M, APLIX or VELCRO hook-and-loop system). A patch ofa corresponding loops component may be disposed at a landing zone on theoutside front waist region of the diaper, so as to enable attachmentwhen the hooks patch is pressed against the landing zone. Anotherexample may have a fastener consisting of a patch of material bearing anadhesive effective to adhere to a smooth surface disposed at the landingzone. Upon being tugged laterally by an applier during application,and/or with lateral tension resulting from application and/or thewearer's movements, longitudinal force components of tension forces inthe fastening member, acting at the edges of the fastener patch, canurge its longitudinally outer edges up and away from the landing zone,thereby causing a sub-optimal fastener attachment to the landing zone,or weakening the fastener's hold at the landing zone, or even causingthe fastener's hold to fail—which may allow the diaper to come loose orfall free of the wearer.

In some circumstances, stresses in the fastening member resulting fromlateral tension may concentrate in the end region near or at the inboardedges of the fastener zone. As a result, the likelihood of a tearbeginning at the location of stress concentration is increased. Forexample, stresses may be concentrated at locations where the fasteningmember narrows to an end region, particularly if there is an abruptstructural discontinuity, such as created by the presence of, forexample, the edge of a patch of a relatively stiffer material adhered toa substrate material. Tearing may occur in the end region, at or nearthe fastener zone, when the applier tugs on the fastening member toapply the diaper; or the end region may tear at or near the fastenerzone from stresses resulting from the wearer's movements.

The above-described events, i.e., panel region buckling/flipping,fastener dishing, and tearing, may be deemed problematic because theymay result in less than optimum performance and/or appearance, failureof the product, and consumer dissatisfaction.

Likelihood of the problems identified above may be decreased by the useof relatively more robust materials to form the fastening member. Amaterial that is more robust, and therefore, stiffer and more resistiveto buckling and tearing, may be used to form the panel region and/orextensible zone. Robustness of a material such as a stretch laminate canbe increased, for example, by the use of materials having greater basisweights and/or densities. Similarly, increasing the bending stiffness ofa fastener patch by selection of a thicker and/or denser patch materialmay make it more resistive to dishing.

These approaches, however, also may have undesirable consequences. If afastener patch is too stiff and unyielding, when fastened at thewearer's waist it may feel like an unyielding object and be a source ofdiscomfort for the wearer under certain circumstances. Increasing thestrength of a stretch laminate may increase its stiffness, but decreaseits extensibility and pliability, as well. Increasing the stiffness of amaterial that is against the wearer's skin in a region of the bodysubject to movement and bending may increase likelihood of discomfortfor the wearer, and promote marking, irritation and chafing of thewearer's skin. For the manufacturer of disposable diapers, acceptablebut relatively more robust materials may be relatively more expensive.If fastening members are not extensible, or not sufficiently so, then itmay be necessary to build additional stretch features into, e.g., thewaist regions of the chassis, if assurance of a comfortable andsnug-fitting diaper is to be maintained.

From the foregoing it can be appreciated that the design of a fasteningmember involves a variety of concerns, and that a great number ofvariables and permutations in the combinations of materials, featuresand structures used is possible. Changing one material, feature orstructure to address one concern may give rise to other concerns. A needfor improvements in the combination of materials, features andstructures used, that satisfactorily address and reduce concerns forcomfort, performance and manufacturing cost of the fastening member andits associated wearable article, always exists.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, like numerals or other designations designate likefeatures throughout the views.

FIG. 1 is a simplified depiction of a wearable article in the form of adiaper, shown extended and laid flat, viewed from above, wearer-facingsurface up;

FIG. 2 is a depiction of an example of a fastening member, laid flat andviewed from above;

FIG. 3 is a depiction of an example of a fastening member, laid flat andviewed from above;

FIG. 4 is a depiction of an example of a fastening member, laid flat andviewed from above;

FIG. 5 is a depiction of an example of a fastening member, laid flat andviewed from above;

FIG. 6 is a depiction of an example of a fastening member, laid flat andviewed from above;

FIG. 7 is a depiction of an example of a fastening member, laid flat andviewed from above;

FIG. 8 is a depiction of an example of a fastening member, laid flat andviewed from above;

FIG. 9 is a depiction of a simplified schematic, exploded lateral crosssection through an example of a fastening member, taken along a stretchdirection;

FIG. 10A is a reproduction of a CAD drawing depicting an example of afastening member, laid flat and viewed from above;

FIG. 10B is a reproduction of a CAD drawing depicting an example of afastening member, laid flat and viewed from above;

FIG. 10C is a depiction of a simplified schematic, exploded lateralcross section through the example of the fastening member depicted inFIG. 10A;

FIG. 11 is an elevation view showing an apparatus for testing thebending stiffness of materials;

FIG. 12 is a front elevation view showing a plunger for use with theapparatus of FIG. 11;

FIG. 13 is a side elevation view showing a plunger for use with theapparatus of FIG. 11; and

FIG. 14 is a graph showing Peak bending load and slope calculation areason bending curve.

DETAILED DESCRIPTION OF THE INVENTION

For purposes of this Description, it is intended that the followingterms have the meanings set forth:

As used herein, the term “extensible” refers to the property of amaterial, wherein: when a biasing force is applied to the material, thematerial can be extended to an elongated length of at least 110% of itsoriginal relaxed length (i.e. can extend 10%), without a rupture orbreakage that renders the material unusable for its intended purpose. Amaterial that does not meet this definition is considered inextensible.In some embodiments, an extensible material may be able to be extendedto an elongated length of 125% or more of its original relaxed lengthwithout rupture or breakage that renders the material unusable for itsintended purpose. An extensible material may or may not exhibit recoveryafter application of a biasing force.

Throughout the present description, an extensible material is consideredto be “elastically extensible” if, when a biasing force is applied tothe material, the material can be extended to an elongated length of atleast 110% of its original relaxed length (i.e. can extend 10%), withoutrupture or breakage which renders the material unusable for its intendedpurpose, and when the force is removed from the material, the materialrecovers at least 40% of its elongation. In various examples, when theforce is removed from an elastically extensible material, the materialmay recover at least 60% or at least 80% of its elongation.

“Inboard”, and forms thereof, with respect to features of a fasteningmember, means furthest from or in a direction away from the free distalend.

An “inboard- and longitudinally inward-pointing vertex”, with respect toa feature of a lateral edge of a wearable article fastening member, laidflat and horizontally, viewed from above, is one in which a line equallydividing the angle formed by the vertex, together with the portions ofthe lines forming the vertex, form an arrow that points at leastpartially longitudinally inwardly on the fastening member and away froma lateral line perpendicular to the wearable article longitudinal axisand intersecting the longitudinally outermost point along the lateraledge, and at least partially in a laterally inboard direction. Referringto FIG. 2, such inboard direction is indicated by arrow 3 (perpendicularto longitudinal axis 24); longitudinally inward directions are indicatedby arrows 4 (parallel to longitudinal axis 24, and pointing away fromlateral lines 6); and examples of inboard and longitudinally inwarddirections are indicated by arrows 5, formed at depicted examples ofidentifiable inboard- and longitudinally inward-pointing vertices 7.

“Junction line,” with respect to a fastening member comprisingcomponents that are discrete from other components of a wearablearticle, which fastening member is welded, bonded, adhered or otherwiseattached to the wearable article, means a longitudinal line, parallelwith a longitudinal axis of the wearable article, across the fasteningmember through the inboard-most point at which the fastening member or aportion thereof is extensible in response to a lateral tension forceimposed thereon. Note: In some examples of fastening members, anextensible zone might have an irregular shape or orientation, or consistof a plurality of extensible portions; in such examples, the point atwhich such shape, orientation or extensible portions are closest to alongitudinal axis of a wearable article will mark the location of thejunction line. “Junction line,” with respect to a fastening membercomprising one or more components that are not discrete from, butrather, integral with, one or more components of a diaper chassis thatis disposed in an opened, extended position and laid flat andhorizontally, viewed from above, means either—(a) a longitudinal linealong the fastening member and integral chassis component, parallel tothe wearable article longitudinal axis, and aligned with thelongitudinal edge of the chassis at its narrowest point, on the sidefrom which the fastening member extends, or (b) a longitudinal lineacross the fastening member through the inboard-most point at which thefastening member or a portion thereof is extensible—whicheverlongitudinal line is most outboard along the fastening member, subjectto the Note immediately above.

“Lateral” (and forms thereof), with respect to a line lying in a planesubstantially occupied by a wearable article fastening member laid flatand horizontally, viewed from above, relates to a directionsubstantially perpendicular to a longitudinal axis of the wearablearticle. “Lateral” and “width” (and forms thereof), with respect tofeatures of a wearable article fastening member, relates to a direction,or generally following a direction, partially or entirely perpendicularto a longitudinal axis along the wearable article. “Lateral” and “width”(and forms thereof), with respect to features of a diaper chassis,relates to a direction substantially parallel to the lateral axis of thechassis.

“Lateral axis” with respect to a wearable article adapted to be worn bya wearer, means an axis perpendicular to the longitudinal axis, andequally dividing the longitudinal length of the article.

Where features or elements of claims set forth herein are identified as“lines” or “line segments” or “points”, such lines, line segments orpoints are not actual physical features themselves unless otherwisespecified, but rather, are geometric references intended for use indescribing locations on a physical structure.

“Longitudinal” and “length” (and forms thereof), with respect to a linelying in a plane substantially occupied by a wearable article fasteningmember laid flat and horizontally, viewed from above, relates to adirection approximately aligned with the wearer's spine when the articlewould be normally worn, with the wearer in a standing or extendedreclining position. “Longitudinal” and “length” (and forms thereof),with respect to features of a fastening member, relates to a direction,or generally following a direction approximately aligned with thewearer's spine when the article would be normally worn, with the wearerin a standing or extended reclining position. “Longitudinal” and“length” (and forms thereof), with respect to features of a diaperchassis, relates to a direction approximately aligned with the wearer'sspine when the article would be normally worn, with the wearer in astanding or extended reclining position.

“Longitudinal axis” with respect to a wearable article adapted to beworn by a wearer, means an axis approximately aligned with the wearer'sspine when the article would be normally worn, with the wearer in astanding or extended reclining position, and equally dividing thelateral width of the article, the lateral width being measured along adirection generally, parallel to the lateral axis.

“Longitudinal axis” with respect to a diaper chassis having a pair ofopposing lateral waist edges and a pair of opposing longitudinal edges,the diaper chassis being opened and laid flat and horizontally, viewedfrom above, means a line connecting the waist edges and equidistant fromthe longitudinal edges, thus equally dividing the lateral width of thechassis, as illustrated by way of example in FIG. 1 (at referencenumeral 24).

“Longitudinally inner”, and forms thereof, with respect to a fasteningmember laid flat and horizontally, viewed from above, means at or towardits longitudinal middle, between its lateral edges.

“Longitudinally outer”, and forms thereof, with respect to a fasteningmember laid flat and horizontally, viewed from above, means at or towardone of its lateral edges, and away from its longitudinal middle.

“Nonwoven” or “nonwoven material” means a fabric-like web materialformed of fibers of a material (such as a polymeric material) which areneither woven nor knitted.

“Normal”, when used in conjunction with the terms “direction”, “force”and/or “stress” in a web material, refers to a direction approximatelyorthogonal to the macroscopic surface of the web material when laidflat, or approximately orthogonal to a plane that is tangential to themacroscopic planar surface of the web material when the macroscopicsurface of the web material is curved.

“Outboard”, and forms thereof, with respect to features of a fasteningmember, means at or in a direction toward its free distal end.

“Overlap” (and forms thereof), when used to describe a disposition oftwo or more discrete layers forming a fastening member, means that onelayer lies, at least partially, vertically over or beneath the other(s)when the member is laid flat in horizontal position, as viewed fromabove. Unless otherwise specified, “overlap” is not intended to imply orbe limited to meaning that the layers are in direct contact with eachother, without any intermediate layers or other materials or structuresbetween them.

“Stiffness”, when capitalized, refers to a property of a portion of afastening member as identified and determined by application of theStiffness Test set forth herein.

“Stretch laminate” means an extensible and elastic web materialcomprising a combination of an elastic polymeric material layered,laminated or interspersed with a nonwoven material.

FIG. 1 generally depicts a simplified representation an example of awearable article, in the form of a diaper 1, as it might appear in anopened, extended position, laid flat and horizontally, body-facingsurface up, and viewed from above. Diaper 1 may have a chassis 10,longitudinal edges 23, longitudinal axis 24, lateral axis 25, frontwaist region 11, front waist edge 12, rear waist region 13, and rearwaist edge 14, and an absorbent core (not shown) disposed between layersof the chassis 10. Chassis 10 may have a pair of oppositely-orientedfastening members 50 a, 50 b extending laterally from a waist region 11or 13. A fastening member 50 a may be a discrete component affixed to aportion of chassis 10 along a line as suggested on the left side ofFIG. 1. In another example, however, a fastening member 50 b may be acomponent that is not discrete from the chassis 10, but rather, may beintegral with a chassis component such as a backsheet, forming anextension thereof, such as suggested on the right side of FIG. 1.

Each of fastening members 50 a, 50 b may have a respective fastener zone71 that includes a fastener 70 disposed at or near its outboard end. Inone example, a fastener 70 may be a patch of hook material constitutingthe hook components of a hook-and-loop fastening system (such as a 3M,APLIX or VELCRO hook-and-loop system). In this example, thegarment-facing surface of front waist region 11 may have a laterallyextended landing zone 22 bearing a patch or strip of loop materialconstituting the cooperating loop component of the hook-and-loopfastening system. In another example, a fastener 70 may be a patch ofadhesive-bearing material, and landing zone 22 may bear a patch ofadhesive-receiving material having smooth surface features and/orchemistry effective to provide an adhesive bond upon contact with afastener 70. Other examples of fasteners include but are not limited tofastening elements described in co-pending U.S. application Ser. No.11/895,169. Other examples may include any other cooperating engagingand receiving surfaces or components adapted to effect fastening,respective components of which may be disposed on either fastening zone71 or landing zone 22, or another location of the wearable article asdesired. A fastener 70 also may include groups of separatelyidentifiable fastening elements such as a plurality of discrete patchesof adhesive-bearing material, discrete patches of hooks, etc. In any ofthe above examples as well as other possible examples, the lateralextent of a landing zone 22 across front waist region 11 as suggested inFIG. 1 provides for attachment of fasteners 70 at laterally varyinglocations along the front waist region 11, and thereby, adjustability ofthe waist opening size and snugness of the diaper as it is being appliedto a wearer.

FIG. 3 depicts an example of a fastening member 50 a shown apart from awearable article. The fastening member 50 a has a first longitudinallyoutermost lateral edge 68, a second longitudinally outermost lateraledge 69, and an outboard end 54. In examples such as those in which thewearable article is a diaper, in order to comfortably accommodate thewearer's movements while promoting a snug fit (and thus, optimalappearance and avoidance of leakage of the wearer's exudates), it may bedesirable to form fastening member 50 a with an extensible zone 66,which may comprise a laminate that is extensible along a stretchdirection 67. In all examples discussed herein, extensible zone 66 maycomprise a web or laminate web that is elastically extensible.Extensible zone 66 may extend between inboard and outboard extensiblezone extents 86, 87. Outboard extensible zone extent 87 is a line drawnlongitudinally through the outboard-most extent of the location(s) ofextensible zone 66. (In some examples of fastening members, anextensible zone might have an irregular shape or orientation, or consistof a plurality of extensible portions; in such examples, the point atwhich such shape, orientation or extensible portions are farthest from alongitudinal axis of a wearable article will mark the location of theoutboard extensible zone extent 87.) In examples having mechanicalactivation as described below, forming extensible zone 66, extensiblezone extents 86, 87 may fall along inboard and outboard lines at which aregion of mechanical activation is bounded. For all purposes herein,inboard extensible zone extent 86 is coincident with junction line 51.Fastening member 50 a may be attached to a wearable article in anysuitable manner, including, but not limited to, continuous orintermittent adhesive bonding, compression bonding, heat bonding,ultrasonic bonding, etc. Fastening zone 71 is bounded by fastening zoneinboard extent 88 and fastening zone outboard extent 75; extents 88 and75 are longitudinal lines, parallel with the longitudinal axis of thewearable article, along the inboard-most and outboard-most locations atwhich a fastener is located. Inboard fastener zone corners 72 and 73 arerespective points on lateral edges 68, 69 intersected by fastener zoneinboard extent 88. Note: In some examples of fastening members, afastener might have an irregular shape or orientation, or consist of aplurality of discrete fastening elements; in such examples, the pointsat which such shape, orientation or elements are closest to and farthestfrom a longitudinal axis of a wearable article will mark the locationsof the fastening zone inboard and outboard extents 88 and 75,respectively.

A junction line 51 on the fastening member can be identified as definedabove, and intersects first and second outermost lateral edges 68, 69 atfirst and second longitudinally outermost junction points 52, 53. Firstand second line segments 76, 78, connecting first and second junctionpoints 52, 53 and first and second inboard fastener zone corners 72, 73,respectively, can be identified. An end region 55 may project in anoutboard direction from outboard extensible zone extent 87, and includean intermediate region 57. End region 55 may have a fastener 70 disposedat or near the outboard end 54 thereof. One or more layers of materialforming end region 55 may be partially or entirely integral andcontinuous with layer(s) of material forming panel region 56, or endregion 55 may be formed of differing or supplemental materials attachedto panel region 56.

As noted in the Background, fastening members of a diaper may bedesigned and situated to wrap around a wearer's hips. As a result, theymay be in contact with the skin at the wearer's hips while the diaper isbeing worn. Additionally, while a diaper is being worn the fasteningmembers will sustain and transfer varying tension forces, particularlywhen the wearer is active and bending at the hips. These tension forceshave normal force components acting on the wearer's skin. Thus, it maybe desirable that the material forming the skin-contacting portions of afastening member 50 a be selected with the objectives of maximizingextensibility, pliability and surface area. Increasing these variablesgenerally may help to more evenly distribute normal forces over agreater skin surface area, provide for easier accommodation of movement,and reduce the likelihood of skin marking and chafing.

Within the group of laminates of the kind often used for diapercomponents, greater extensibility may translate to greater pliability,as a result of reducing material thickness and/or density. Accordingly,it may be desirable that the extensible zone of fastening member 50 a,be formed of a material, for example, a stretch laminate, having arelatively high extensibility. Examples of stretch laminates that may besuitable for forming an extensible zone are described in PCTApplications No. WO 2005/110731 and Published U.S. Application Nos. US2004/0181200 and US 2004/0193133. Increasing extensibility also mayenable conservation of material, in that comparatively less of acomparatively more extensible material, is required to provide a desiredstretched width to the fastening member. It may be desirable, therefore,that the overall extensibility of a fastening member, expressed in termsof the ratio of the amount of extension in width over unstretched width,in response to a given lateral force load, be at least about aparticular amount.

For example, referring to FIGS. 3 and 4, a reference width WS can beidentified, as the width of the fastening member from inboard extensiblezone extent 86 to fastener zone inboard edge 88. It may be desirable forthe fastening member to be extensible under a laterally-applied tensionload of 8.0 N to at least about 40%, or at least about 50%, or even atleast about 60%, where the percentage is calculated as [(amount ofextension of width WS at 8.0 N lateral tension load)/(unstretched widthWS at zero lateral load)]×100%. For purposes herein, this expression ofextensibility is referred to as “overall extensibilty under load”.

The desirable amount of extensibility may, however, also vary inrelation to the length of the fastener zone 71 and/or the length of theextensible zone 66. In FIG. 5, the length of the fastener zone inboardedge is shown as LFP, and the length of the inboard extensible zoneextent 86 is shown as LEP.

Referring to FIGS. 3 and 5, it may be desirable that the fasteningmember be extensible under a laterally-applied tension load of 2.1N/cm-LFP (2.1 N per each cm fastener inboard edge length LFP) to atleast about 45%, or at least about 55%, or even at least about 65%,where the percentage is calculated as [(amount of extension of width WSat 2.1 N/cm-LFP lateral tension load)/(unstretched width WS at zeroload)]×100%. For purposes herein, this expression of extensibility isreferred to as “extensibility under load per fastener zone length”.

Still referring to FIGS. 3 and 5, it may be desirable that the fasteningmember be extensible under a laterally-applied tension load of 1.0N/cm-LEP (1.0 N per each cm extensible zone inboard edge length LEP) toat least about 45%, or at least about 55%, or even at least about 65%,where the percentage is calculated as [(amount of extension of width WSat 1.0 N/cm-LEP lateral tension load)/(unstretched width WS at zeroload)]×100%. For purposes herein, this expression of extensibility isreferred to as “extensibility under load per extensible zone length”.

For purposes of the description herein, a “highly extensible fasteningmember” is any fastening member having an extensibility valueapproximately equal to or exceeding any of the lowest overallextensibility under load, extensibility under load per fastener zonelength, or extensibility under load per extensible zone length,described above.

At the same time, it may be desirable that a fastening member 50 a bemaximized in length L (the length of junction line 51) and surface area,to the extent feasible, for three reasons: first, to distribute thenormal forces acting against the skin over a greater skin area, forgreater comfort and less likelihood of skin marking and chafing; second,to distribute tension forces along a longer portion of the chassis inthe waist region, thus minimizing the likelihood of tearing at thechassis; and third, to maximize skin coverage at the hips, for purposesof appearance of the diaper.

Thus, extensibility, pliability and fastening member length/surface areaare several (among a number of) variables which may be adjusted toaffect comfort and performance. Adjustment of these variables, however,may have undesirable effects. For example, increasing length L andsurface area of the fastening member 50 a, increases the likelihood thattop or bottom edges of the panel region 56 may buckle and flip away fromthe wearer while the diaper is being worn, detracting from theappearance of the diaper and compromising some of the benefits of theincreased length and surface area. Referring to FIG. 3, withoutintending to be bound by theory, it is believed that first and secondline segments 76, 78 approximately show longitudinally outermost linesof tension in the fastening member between first and secondlongitudinally outermost junction points 52, 53 and first and secondinboard fastener zone corners 72, 73, that would exist absent shapefeatures of fastening element 50 a discussed in more detail below.Without intending to be bound by theory, it is believed that, as stressis distributed through an extensible web material when it is stretchedunder lateral load as in the configuration shown in FIG. 3, materialproximate to line segments 76, 78 may be subject to varying levels oflongitudinally inwardly-directed, transmitted longitudinal forcecomponents, which may tend to pull material outside line segments 76, 78longitudinally inwardly. In designs not having features hereindescribed, this may cause the material forming the panel region 56and/or the extensible zone 66 to buckle and even flip away from thewearer, approximately along the longitudinally outermost lines oftension. As a result of such buckling and/or flipping, normal forces inthe fastening member acting on the skin may be distributed over lessskin area, and appearance of the diaper may be compromised. Increasingthe pliability of the fastening member material may lessen its abilityto resist such buckling/flipping, and may thereby exacerbate theproblem.

In addition, without intending to be bound by theory, it is believedthat increasing the length L and/or pliability of fastening member 50 amay increase a tendency to cause longitudinally inward-directedlongitudinal force components to be distributed through the fasteningmember so as to act in concentrated areas along the longitudinally outeredges of the fastener zone 71. This effect, coupled with movements bythe wearer that may urge the fastener zone 71 to flex such that itslongitudinally outer edges move away from the wearer, may cause thelongitudinal forces to be directed so as to further urge the edges offastener zone 71 away from the wearer. As a result, the edges of thefastener zone 71 may be urged away (dish) from the landing zone to whichfastener 70 is attached, which in turn, may cause the hold of thefastener 70 to the landing zone to be weakened, or even to fail.

The problems identified above may be mitigated by the use of materialshaving a higher planar bending stiffness for, e.g., the panel region 56,extensible zone 66, end region 55, fastener zone 71, and areasbetween/around them. As these areas are stiffened, the likelihood ofundesired buckling of the extensible zone, and lifting of edges of thefastener zone, is decreased. This approach, however, may haveundesirable effects. Stiffening the panel region 56 and/or extensiblezone 66 may necessarily require using materials that are thicker and/ormore dense, and add material cost. Stiffer material in panel region 56and/or extensible zone 66 may undesirably feel less soft, supple andcloth-like to the applier and the wearer. It also may be lessextensible. A reduction in extensibility in a fastening member meansthat, unless snugness and comfort of the article are to be compromised,features imparting lateral extensibility about the waist must beincorporated into other components of the diaper, for example, the waistregions 11, 13 of the chassis 10. Excessively increasing stiffness inthe fastener zone 71 may create the feel of an unyielding object againstthe diaper at the wearer's abdomen, and may be a source of discomfortfor the wearer, particularly when the wearer is sitting and/or bendingforward at the hips. Increasing stiffness in the fastener zone also maynecessitate increasing material thickness and/or density, adding cost.

Other approaches, however, may be employed.

As noted, FIGS. 3 and 4 depict examples of a fastening member, 50 a and50 b. Potentially advantageous features in these examples will now bedescribed. (FIG. 3 depicts a fastening member 50 a comprising discretecomponents as may be attached to a wearable article; FIG. 4 depicts afastening member 50 b comprising components integral with components ofa wearable article.)

A fastening member may be integrally-formed. “Integrally-formed,” forpurposes herein and with respect to a fastening member having a fastenerattached thereto, means a fastening member that has one or both of thefollowing characteristics: (1) It has no inboard- and longitudinallyinward-pointing vertex lying along its first or second outermost lateraledges, and lying between the inboard edge of the fastener zone and ajunction line; and/or (2) there is at least one longitudinal line alongthe end region, along which a layer of material forming the end regionis longitudinally coextensive with, or longer than, a layer of materialforming an extensible zone. These characteristics structurally andfunctionally distinguish a fastening member having one or both of themfrom a fastening member having a “tape” type construction, in which acomparatively short tab member, bearing a fastener and forming the endregion of the fastening member, joins a relatively longer side panelregion of the fastening member, in which such vertices are present andno such line exists.

Without intending to be bound by theory, it is believed that anintegrally-formed fastening member is substantially less prone tobuckling/flipping in the panel region and/or extensible zone asdescribed above, as compared with possible constructions not havingthese characteristics.

Thus, referring to FIGS. 3, 4 and 9, for example, a layer of material inwhole or in part forming end region 55, such as first surface layer 62or second surface layer 63 may also form a part of panel region 56 andextensible zone 66. It can be appreciated that there may be at least oneline (in the example depicted, there are more than one), along which anend region layer of material (such as first surface layer 62, secondsurface layer 63 and/or reinforcing layer 61) may be longitudinallycoextensive with, or longer than, a layer of material forming theextensible zone 66. In FIGS. 3 and 4 it can be seen that one or both ofoutermost lateral edges 68, 69 can be shaped so as to have no inboard-and longitudinally inward-pointing vertices lying therealong, betweenthe inboard edge 88 of the fastener zone 71 and a junction line 51. Itcan also be appreciated that, even where end region 55 is formed ofmaterials or components that are discrete from materials forming panelregion 56, which are affixed to an outboard portion of panel region 56,when end region 55 is appropriately shaped there still may be at leastone line along which an end region layer of material may belongitudinally coextensive with, or longer than, a layer of materialforming the extensible zone 66, and/or, one or both of outermost lateraledges 68, 69 can be shaped so as to have no inboard- and longitudinallyinward-pointing vertices lying therealong, between the inboard edge 88of the fastener zone 71 and a junction line 51, thus forming anintegrally-formed fastening member.

While an integrally-formed fastening member may be less prone to panelregion buckling and flipping, the construction may cause transfer oflongitudinal forces outboard along the fastening member, toward and intothe end region. Unless these forces are managed by other features,integrally-formed construction may, in some circumstances, lead toincreased likelihood of fastener zone dishing.

Additional possible advantageous features of a fastening member outershape may be identified in FIGS. 3 and 4. It can be seen that one orboth of the first and second longitudinally outermost lateral edges 68,69 may be given a profile that traverses line segments 76, 78. Thisfeature may provide certain advantages. Without intending to be bound bytheory, it is believed that it serves to direct lines of tension, andlongitudinal force components thereof, away from the lateral edges andtoward the longitudinal middle of the fastening member, thus furtherreducing the likelihood of buckling/flipping in the panel region and/orextensible zone. It also is believed such direction of longitudinalforce components toward the longitudinal middle decreases the leveragesuch longitudinal force components may otherwise exert at the lateralouter edges of fastener zone 71 that tend to urge it dish.

Adjusting other aspects of the shape of a fastening member also may beeffective at reducing fastener dishing, and panel region buckling andflipping, while allowing for generous skin coverage. Referring to FIG.5, fastening member 50 a may have junction line 51, outboard end 54,fastener zone 71, fastener 70, and extensible zone 66. Extensible zone66 may be bounded by an inboard extensible zone extent 86 and anoutboard extensible zone extent 87. Extensible zone 66 may beelastically extensible between extents 86, 87 along lateral stretchdirection 67. Extents 86 and 87 may be, in one example, lines alongwhich activation of a stretch laminate forming fastening member 50 abegin and end, such that fastening member 67 is substantiallyelastically extensible in extensible zone 66, but not substantiallyelastically extensible in the areas inboard and outboard of extents 86and 87, respectively.

For reference purposes, an acting width WA in an example such asdepicted in FIG. 5 may be identified as the width of fastening member 50a from the fastener zone outboard edge 75, lying along longitudinal lineW0, to inboard extensible zone extent line 86, lying along longitudinalline W100. Width WA may be divided into four equal portions, bylongitudinal line W25 lying at 25% of acting width WA; longitudinal lineW50 lying at 50% of acting width WA, and longitudinal line W75 lying at75% of acting width WA, and bounded by lines W0 and W100. Fasteningmember 50 a may have varying lengths L0, L25, L50, L75 and L100measurable along lines W0, W25, W50, W75 and W100, respectively, wherethey intersect with first and second longitudinally outermost lateraledges 68, 69, as shown by way of example in FIG. 5.

Without intending to be bound by theory, it is believed thatprogressively improved results may be achieved, that is, a combinationof—(a) effectively controlled dishing of the fastener along with (b) afastener that is large enough in contact surface area to provideeffective fastening/holding capability; (c) effectively controlledbuckling and foldover of the material forming the fastening member and(d) satisfactory skin coverage—may be achieved, when L0, L25 and L50fall approximately above the following lower limits, expressed as apercentage of L100. Further, in some examples, results may be improvedif L0, L25 and L50 fall approximately below the following upper limits,expressed as a percentage of L100:

/L100 Possible Possible lower limit upper limit L0 25%, or 65%, or 30%,or even 50%, or even 40% 45% L25 30%, or 60%, or 35%, or even 55%, oreven 40% 50% L50 50%, or 100%, 60%, or even 90%, or even 65% 70%

Still referring to FIG. 5, other possible characteristics of the shapeof a fastening member 50 a can be seen. Outermost lateral edges 68, 69each may have profiles defining one or more inflection points 94, atwhich the direction of curvature of the profile changes. Withoutintending to be bound by theory, it is believed that including at leastone such inflection point 94 on at least one of outermost lateral edges68, 69 approximately between lines W25 and W50 is effective fordiffusing longitudinal force components away from such edge, so as toreduce the likelihood of dishing of a fastener zone. Inclusion ofseveral inflection points 94 may increase the effect. Thus, inflectionpoints 94 may be included approximately between lines W25 and W50 oneach of outermost lateral edges 68, 69. Inflection points may also beincluded on one or both of outermost lateral edges 68, 69 approximatelybetween lines W50 and W75. Additional inflection points 94 may be added,as shown by way of example in FIG. 5 along first outermost lateral edge68, suggesting two inflection points 94 approximately between lines W25and W50, and two inflection points 94 approximately between lines W50and W75.

Still referring to FIG. 5, without intending to be bound by theory, itis also believed that, where the fastener comprises or is disposed on apatch of material that adds stiffness to the fastener zone 71, there isan effective relationship between the fastener zone inboard edge lengthLFP, extensible zone outboard edge length LED (measured along outboardextensible zone extent 87), and extensible zone inboard edge length LEP(measured along inboard extensible zone extent line 86). It is believedthat chances of minimizing fastener dishing and buckling/flipping of thepanel region 56 may be enhanced when LFP lies within a range from about50% to about 75%, or from about 55% to about 75%, or from about 60% toabout 75%, of LED. It is also believed that chances of minimizingfastener dishing and buckling/flipping of the fastening member 50 a maybe enhanced when LFP lies within a range from about 35% to about 65% ofLEP, or about 40% to about 50% of LEP, or even about 40% to about 45% ofLEP.

Additional features are apparent from FIGS. 3-6, and may be helpful toreduce the likelihood of panel region buckling/flipping and/or fastenerzone dishing. Referring specifically to FIG. 5, it can be seen that L0(which corresponds to the length of the outboard edge 75 of fastenerzone 71) may be less than LFP (which corresponds to the length of theinboard edge 88 of fastener zone 71). Outboard fastener zone corners 92and 93 are respective points on lateral edges 68, 69 intersected byfastener zone outboard extent 75. Referring to FIG. 6, first and secondfastener zone lateral edge lines 90, 91 may be identified, which connectfirst inboard fastener zone corner 72 with first outboard fastener zonecorner 92, and second inboard fastener zone corner 73 with secondoutboard fastener zone corner 93, respectively. As a result of differinglengths of L0 and LFP (see FIG. 5), referring to FIG. 6, angles α and βare formed by the intersection of lateral edge lines 90, 91 and laterallines 110, 111 that are perpendicular to junction line 51 as shown. Forpurposes herein, these angles α and β are referred to as “fastener zonelateral edge angles.” Without intending to be bound by theory, it isbelieved that shaping the fastening member such that these fastener zonelateral edge angles α and β lie between about 0 degrees and about 30degrees, or between about 2 degrees to about 20 degrees, or betweenabout 2 degrees to about 15 degrees, or even between about 5 degrees and15 degrees, extending outwardly from the lateral lines 110 and 111,substantially helps reduce the likelihood of fastener zone dishing as aresult of the effects of distributing force components within thefastening member, across the fastener zone. Angles α and β need not bethe same. They may be the same, or they may be different. One or bothmay fall within one or more of the ranges set forth above.

Referring again to FIG. 5, for purposes of best positioning of afastener relative to the location at which an applier is likely to graspthe fastening member, it may be desirable to locate fastener 70 suchthat it lies entirely outboard of line W25.

For purposes of minimizing the cost of a fastening member, it may bedesirable to make it as narrow in lateral width as practical, so as toconserve material. However, it may also be desirable to provide forsufficient width of the fastening member as the article is applied to awearer. Referring to FIG. 5, it is believed, therefore, that impartingextensible zone 66 with an unstretched extensible zone width (i.e., thedistance between inboard and outboard extensible zone extents 86, 87when extensible zone 66 is not stretched) that exceeds about 50% of theacting width WA, is effective to satisfy these conflicting purposes. Atthe same time, in the interest of controlling force transmission to thefastener zone, it may be undesirable for the unstretched extensible zonewidth to exceed about 75 percent of the acting width WA. Thus, it may bedesirable that the extensible zone 66 have a width from about 50 percentto about 75 percent of the acting width of the fastening member. It alsomay be desirable that outboard extensible zone extent 87 be locatedbetween W25 and W50.

As noted, an integrally-formed fastening member may in somecircumstances promote transfer of longitudinal force components to theedges of the fastener zone, which may cause the fastener to dish. Thismay cause it to peel (disengage) away from its associated landing zonewhen in use. For this reason, utilizing a fastener of a type having agood resistance to peel (by disengagement) may be desired. A fastenercapable of sustaining a load of least about 1 N, or at least about 2 N,or even at least about 3 N, before separation in peel mode, may bedesired.

Additionally, as noted above, increasing the Stiffness of fastener zone71 may serve to help reduce the likelihood or extent of fastenerdishing. A fastener zone 71 having a Stiffness of at least about 1,500N/m may be helpful. As also noted above, however, effecting an excessiveincrease in the stiffness of fastener zone 71 may be undesirable becauseit may result in the feel of an unyielding object against the diaper atthe wearer's abdomen, and may be a source of discomfort for the wearer,particularly when the wearer is sitting and/or bending forward at thehips. Additionally, increasing stiffness in the fastener zone maynecessitate increasing material thickness and/or density, adding cost. Afastener zone 71 may be deemed too stiff under certain circumstances,for these reasons. Thus, it may be desirable to have an upper limit of,for example, 9,000 N/m, on the amount of Stiffness of the fastener zone71 that is imparted.

At the same time, imparting a Stiffness to fastener zone 71 above someminimum value may by itself be insufficient to satisfactorily preventdishing. Without intending to be bound by theory, however, it isbelieved that the shaping of fastening member 50 as described above maybe unexpectedly synergistic in combination with a limited amount ofStiffness of the fastener zone 71. In other words, without intending tobe bound by theory, it is believed that the shaping described abovemagnifies the effect of adding to the Stiffness of fastener zone 71, inreducing or preventing dishing. Accordingly, it is believed that dishingcan be effectively and satisfactorily reduced or prevented if fastenerzone 71 has a Stiffness of at least about 1,500 N/m, or 2,500 N/m, or3,500 N/n, or 4,000 N/m, and the fastening member has one or more of theshape and construction characteristics identified and described herein.In order to reduce the likelihood that the fastener zone is perceived astoo stiff, possibly uncomfortably so, by the wearer and/or applier,however, it may be desirable that the fastener zone has a Stiffness ofno more than about 9000 N/m, or 7,500 N/m, or even 6,000 N/m.

Referring again to FIGS. 3 and 4, fastener zone 71 may overlap one ormore underlying layers of materials in end region 55 which may bothcontribute to Stiffness of fastener zone 71, and may also extend fromfastener zone 71 in an inboard direction. An intermediate region 57 mayinclude such underlying material(s), and have its own Stiffness. Ifintermediate region 57 is imparted with an intermediate Stiffness thatis less than the Stiffness of fastener zone 71, but greater than theStiffness of panel region 56 and/or extensible zone 66, this may havethe advantages of bearing and resisting longitudinal force componentsthat develop within the panel region 56, and preventing their transferto fastener zone 71, thus reducing the likelihood of dishing of fastener70, as well as reducing the likelihood of buckling/flipping in panelregion 56, without substantially compromising wearer comfort afforded bya highly-extensible, pliable panel region 56. Thus, for example,intermediate region 57, or a portion thereof, may be imparted with anintermediate Stiffness of between about 200 N/m and about 1000 N/m, orbetween about 300 N/m and about 750 N/m, or even between about 400 N/mand about 600 N/m. Intermediate region 57 or a portion thereof, as wellas panel region 56, may be imparted with any additional Stiffnesscharacteristics, including variations and gradients thereof, asdescribed in co-pending U.S. application Ser. No. 11/895,169.

A fastening member may have an extensible zone 66 formed of a stretchlaminate that has been activated by mono-axial stretching of the sectionof the laminate which contains the laminated-in elastomeric materiallayer 64, or a portion thereof, in a manner described in more detail,for example, in U.S. Pat. No. 4,834,741, and in published PCTapplications Nos. WO 1992/015446 and WO 1992/015444, which areincorporated herein by reference. In addition, extensible zone 66 mayinclude force-focusing features such as described in U.S. PublishedApplication No. 2007/0142815. Referring to FIG. 7, a fastening member 50a may have an extensible zone 66 having regions of varying moduli ofelasticity. For example, extensible zone 66 may have a relatively highermodulus region 101, and relatively lower modulus regions 100 assuggested. High modulus region 101 may be disposed at or about thelongitudinal center of extensible zone 66 as suggested in FIG. 7, or maybe disposed at other locations. In the example suggested in FIG. 7,however, relatively high modulus region 101 will bear a greaterproportion of lateral tension forces per surface area, thus “focusing”lateral tension forces toward the longitudinal center of the fasteningmember. Without intending to be bound by theory, it is believed that, asa result, stresses acting along longitudinally outermost edges 68, 69are reduced while overall lateral tension in the fastening member ismaintained such that the article maintains good fit, while likelihood offastener zone dishing may be reduced. Other examples of materialsincluding zones of differing moduli are described in, for example, PCTApplication Nos. WO 2007/069227 and WO 2008/084449.

In addition to being relatively more prone to buckling/flipping, arelatively highly extensible, more pliable material may be less robust,and have less resistance to tearing. This may become an issue, forexample, when an applier tugs on end region 55 in order to apply thediaper to a wearer. If the applier tugs with sufficient lateral force,material forming panel region 56 may tear, particularly at locationswhere stress concentrates, such as, for example, where the fasteningmember shortens to an end region and/or a discontinuity in fasteningmember construction results in an abrupt transition from relatively morepliable portion of the fastening member to a relatively stiffer portionof the fastening member. Referring to FIG. 8, in one example, fastenerzone 71 may comprise a patch of material which, when affixed to asubstrate, creates a combination of the patch material and the substratehaving greater stiffness than that of adjoining substrate alone. Thus,when fastening member 50 a is loaded under lateral tension along stretchdirection 67, stresses may concentrate along fastener zone inboard edge88. Additionally, where, as in the example depicted in FIG. 8, thefastener 70 may occupy a shortened end region, stresses may beespecially concentrated in the substrate along first and secondlongitudinally outermost lateral edges 68, 69, at first and secondinboard fastener zone corners 72, 73. As the manufacturer increases theamount of stretch and/or pliability for the selected material formingpanel region 56 by reducing basis weight, the likelihood of tearing atfirst and/or second inboard fastener zone corners 72, 73 may increase.

In order to improve the ability of the fastening member to withstandand/or diffuse such stress concentrations and reduce the likelihood ofsuch tearing, the manufacturer may form end region 55 of a material orcombination of materials that has greater tensile strength at least inthe lateral direction, or in several directions, than the material(s)forming the extensible zone. As another option, the manufacturer may adda reinforcing layer to end region 55 to form a laminate section at endregion 55 having greater tensile strength in at least the lateraldirection, or in several directions, than the material(s) forming theextensible zone. Either approach may be used to form a strengthened endregion 155. (For purposes of this description, “strengthened,” withrespect to an end region of a fastening member, means an end region thathas greater tensile strength in at least the lateral direction, than thematerial(s) forming the extensible zone).

FIG. 9 schematically depicts a simplified lateral, exploded crosssection of one example of a fastening member 50 a having a strengthenedend region 155. As shown in FIG. 9, a fastening member 50 a may have anextensible zone 66 between inboard and outboard extensible zone extents86, 87, a inextensible inboard zone 83, and a inextensible end region55. A fastening member 50 a may be constructed in several layers and mayhave one or two surface layers 62, 63, which may consist of a nonwovenmaterial, and an elastomeric material layer 64 laminated to and/orbetween the one or two surface layers 62, 63, to form a stretchlaminate. Suitable examples of stretch laminates and elastomeric filmsfor forming panel region 56 and/or extensible zone 66 include thosedescribed in copending U.S. Published Application No. US 2007/0293111.The one or two surface layers 62, 63 may be wider along stretchdirection 67 than the elastomeric material layer 64, and may be bondedtogether in regions forming end region 55 and inboard zone 83. Theinboard zone 83 may be formed of only the two surface layers 62, 63bonded together. The end region 55 may be reinforced by a reinforcinglayer 61 having reinforcing layer inboard edge 89, thereby formingstrengthened end region 155. Reinforcing layer 61 may be disposed in anoverlapping zone 84, in overlapping relationship with elastomericmaterial layer 64. The width of the reinforcing layer 61 and/or thewidth of the elastomeric material layer 64 may be adjusted so that theiredges overlap to form an overlapping zone 84 of desired width. Thereinforcing layer 61 may be formed of, for example, a nonwoven material.Inclusion of reinforcing layer 61 may be used to impart greater tensilestrength in at least the lateral direction, to end region 55, than itwould have absent a reinforcing layer. The reinforcing layer 61 may bedisposed between the surface layers 62, 63 and beneath the elastomericmaterial layer as suggested in FIG. 9, or may be disposed between thesurface layers 62, 63 and above the elastomeric material layer, or onthe outside surface of either of surface layers 62, 63. In anotherexample (not shown), strengthened end region 155 may comprise one layer,or a plurality of layers of material forming a laminate, that isdiscrete from material forming panel region 56, bonded at its inboardedge to the outboard edge of an adjoining material forming panel region56 and/or extensible zone 66, or component thereof. A fastener 70 may beaffixed to an outside surface of strengthened end region 155. Fastener70, and layers 61, 62, 63 and 64 may be laminated together in a laminatestructure, by any suitable adhesive and/or other bonding laminatingtechnique(s). Reinforcing layer 61 and/or strengthened end region 155may be formed of materials selected so as to impart, or contribute toimparting, a desired amount of Stiffness to fastener zone 71 and/orintermediate region 57, as described above.

In the example depicted in FIG. 9, the extensible zone 66 may benarrower in width than the elastomeric material layer 64, and end at alocation inboard of the overlapping zone 84, providing a relativelyinelastic portion including overlapping zone 84, for anchoring thereinforcing layer 61 to elastomeric material layer 64 and transitioningto the strengthened end region.

Referring again to FIG. 8 and FIG. 9, reinforcing layer 61 may be sizedso as to extend from end region 55 in an inboard direction to formstrengthened end region 155, ending on the inboard side at reinforcinglayer inboard edge 89. Reinforcing layer 61 may have a length LR alongits inboard edge 89 extending between first and second longitudinallyoutermost lateral edges 68, 69, and a width WR from the fastener zoneoutboard edge 75 to reinforcing layer inboard edge 89.

In order to ensure an acceptable level of consumer satisfaction with itsproduct, the manufacturer may wish to design and manufacture fasteningmember 50 a so that it will sustain a particular lateral tension loadbefore any failure in the material from tearing,delamination/separation, breaking of bonds, etc. For fastening membersof the type that may be used on diapers, the manufacturer may requireand design fastening members to sustain, for example, at least 18 N, 24N, 30 N or even 34 N of lateral peak tension load before failing, whenpulled at a speed sufficient to accomplish a strain rate in theextensible zone of between about 5 seconds⁻¹ to about 40 seconds⁻¹. Theweakest location of a particular material forming panel region 56 maybe, for example, along its longitudinally shortest dimension, i.e., thepoint at which the smallest longitudinal cross section of material issubject to the stress required to sustain the lateral load (withoutsupport from any stiffening or reinforcing layer). In some examples suchas depicted in FIGS. 8 and 9, and in which a stretch laminate isactivated as described above, surface layers 62, 63 may be laterallyweakened in the activation process. Thus, in the example depicted inFIG. 8, the weakest portion of fastening member 50 a might in somecircumstances be along reinforcing layer inboard edge 89, or along, forexample, outboard extensible zone extent line 87—at which a combinationof activation-weakened material and relatively small longitudinaldimension of extensible zone 66 exists. Accordingly, when a strengthenedend region 155 of a fastening member 50 a having a layered constructionas depicted in FIG. 9, is desirably sized, failure of materials formingthe fastening member 50 a under lateral loading might be expected tooccur, on average, at a location proximate to the strengthened endregion/reinforcing layer inboard edge, rather than elsewhere on thefastening member. It will be appreciated that a width for a reinforcinglayer 61 or a strengthened end region 155 that substantially exceedsthis desirably-sized value may compromise the extensibility of thefastening member, reduce the width of the extensible zone, or may beunneeded to provide the required design strength, and thus, addunnecessary material cost, while a width less than this value mayincrease the likelihood of failure under a lateral load below theintended design load.

Thus, in the examples depicted in FIG. 8 and FIG. 9, reinforcing layer61 may be sized so as to have an affixed width WR overlapping andaffixed to other layer(s) in overlapping zone 84, and so that itsaffixed inboard edge 89 (and thus, the inboard edge of strengthened endregion 155) lies along a line at which the affixed length along inboardedge 89 is of a length LR that is from about 66 percent to about 80percent, or from about 69 percent to about 77 percent, or even fromabout 71 percent to about 75 percent, of the length L of the fasteningmember along junction line 51. Without intending to be bound by theory,it is believed that a reinforcing layer/strengthened end region sizedwithin one or more of these ranges desirably bears and/or reduces stressconcentrations about the fastener zone when the fastening member isunder lateral tension load, and achieves a satisfactory balance betweenminimizing the likelihood that the fastening member will tear underlateral loading in an amount less that its intended design provides,while at the same time minimizing added material costs resulting frominclusion of a strengthened end region.

Other types, and methods of making, a strengthened end region aredescribed in, for example, PCT Applications Nos. WO 2003/039426 and WO2004/082918.

In order to manufacture a fastening member having the features describedherein, a member having the shape and dimensions shown in FIGS. 10A and10B might be cut from a suitable combination laminate, having the layersshown in FIG. 10C. All dimensions shown in FIG. 10B are set forth in thefollowing table, and are expressed in millimeters. (The drawings are notto scale.)

Dimensions in millimeters, FIG. 10B A 90.0 B 35.6 C 40.0 D 59.7 E 21.3 F18.5 G 28.5 H 33.8 I 34.7 J 55.0 K 80.0 L 80.0 M 16.0 N 32.0 O 48.0 P64.0

In cross section the exemplary fastening member may have the generallayered configuration depicted in FIG. 10C. The laminate assembly fromwhich the fastening ear might be cut, including first surface layer 62,elastomeric material layer 64, second surface layer 63 and reinforcinglayer 61 might be formed of materials as follows:

Layer Material Fastener 70 APLIX 963, available from Aplix Fastener UKLtd., Suffold, England Adhesive (between hot melt adhesive, BOSTIKH2988F01, fastener 70 and available from Bostik, Middleton, MA, appliedreinforcing layer 61) at about 150 gsm (grams per square meter)Reinforcing Layer 61 40 gsm monolayer spunbond polypropylene nonwoven,PROWEB, available from Rheinische Kunststoffwerke, Gronau GermanyAdhesive (between hot melt adhesive, BOSTIK H2511, available reinforcinglayer 61 from Bostik, Middleton, MA, applied at about and first surfacelayer 40 gsm 62) First Surface Layer 62 31 gsm high elongation carded(HEC), point- bonded nonwoven, FPN 332D available from Fiberweb,Simpsonville, SC Adhesive (between hot melt adhesive, BOSTIK H2511,available first surface layer 62 from Bostik, Middleton, MA, applied atabout and elastomeric 10 gsm material layer 64) Elastomeric Material 62gsm styrene-butane-styrene film, Layer 64 SOLASTIC, available fromNordenia International AG, Gronau, Germany Adhesive (between hot meltadhesive, BOSTIK H2511, available elastomeric material from Bostik,Middleton, MA, applied at about layer 64 and second 10 gsm surface layer63) Second Surface Layer 63 31 gsm high elongation carded (HEC), point-bonded nonwoven, FPN 332D available from Fiberweb, Simpsonville, SC

Many variations in specific materials and construction approaches may beused to achieve the desired stiffness and stretch levels requiredherein. Other examples of materials and construction approaches areshown in U.S. Published Application Nos. 2007/0143972 and 2007/0157441.

Examples of approaches for rendering the extensible zone extensible aredescribed in U.S. Pat. Nos. 4,107,364 and 4,834,741, and in publishedPCT applications Nos. WO 1992/015446 and WO 1992/015444.

Test Methods

Stiffness Test

Stiffness is measured using a constant rate of extension tensile testerwith computer interface (a suitable instrument is an MTS Alliance underTestWorks 4 software, as available from MTS Systems Corp., Eden Prairie,Minn.) fitted with a 10 N load cell. A plunger blade 2100, shown in FIG.12 (front view) and FIG. 13 (side view), is used for the upper movabletest fixture. Base support platforms 2200, shown in FIG. 11, are used asthe lower stationary test fixture. All testing is performed in aconditioned room maintained at about 23 C±2 C and about 50%±2% relativehumidity. Herein, width and length of the test specimen are a lateralwidth and longitudinal length using the directional conventionscorresponding to the fastening member from which the specimen is cut, as“lateral width” and “longitudinal length” are defined herein.

Components of the plunger 2100 are made of a light weight material suchas aluminum to maximize the available load cell capacity. The shaft 2101is machined to fit the tensile tester and has a locking collar 2102 tostabilize the plunger and maintain alignment orthogonal to base supportplatforms 2204. The blade 2103, is 115 mm long 2108 by 65 mm high 2107by 3.25 mm wide 2109, and has a material contact edge with a continuousradius of 1.625 mm. The bracket 2104 is fitted with set screws 2105 thatare used to level the blade and a main set screw 2106 to firmly hold itin place after adjustment.

The bottom fixture 2200 is attached to the tensile tester with the shaft2201 and locking collar 2202. Two movable support platforms 2204 aremounted on a rail 2203. Each test surface 2205 is 85 mm wide 2206 by 115mm long (into plane of drawing) and made of polished stainless steel soas to have a minimal coefficient of friction. Each platform has adigital position monitor 2208 which reads the individual platformpositions, and set screws 2207 to lock their position after adjustment.The two platforms 2204 are square at the gap edge and the plate edgesshould be parallel front to back. The two platforms form a gap 2209 withan adjustable gap width 2210.

Accurately (±0.02 mm) align the plunger blade 2103 so that it isorthogonal to the top surface of the support platforms 2204 and exhibitsno skew relative to their gap edges. Using the position monitors 2208,accurately set the gap 2210 to 8.00±0.02 mm between the two gap edges ofthe support platforms 2204, with the plunger blade 2103 accurately(±0.02 mm) centered in the gap. Program the tensile tester for acompression test. Set the gauge length from the bottom of the plungerblade 2103 to the top surface of the support platform 2204 to 15 mm.

Set the crosshead to lower at 500 mm/min for a distance of 25 mm. Setthe data acquisition rate to 200 Hz.

Precondition specimens at about 23 C±2 C and about 50%±2% relativehumidity for 2 hours prior to testing. Die cut a test specimen 13 mm inwidth by 25.4 mm in length. If the fastening member from which the testspecimen is to be cut does not have sufficient material for a 13 mm-widetest specimen, use the full width that is available.

Examine the specimen for any exposed adhesive and deactivate any exposedadhesive by applying baby powder to it as necessary. Place the specimenflat onto the surface of the support platform 2204 over the gap 2209with the fastener facing upward. If the particular specimen does notcontain a fastener (for example, a specimen cut from the intermediateregion), orient the specimen such that the fastener side is facing up.Center the specimen across the gap; its length should be parallel to thegap width 2210 and its width should be perpendicular to the gap width2210. Zero the load cell; start the tensile tester and the dataacquisition.

Program the software to calculate the maximum peak bending force (N) andStiffness (N/m) from the constructed force (N) verses extension (m)curve. Stiffness is calculated as the slope of the bendingforce/extension curve for the linear region of the curve (see FIG. 14),using a minimum line segment of at least 25% of the total peak bendingforce to calculate the slope. If the width of the element is not 13 mm,normalize the actual width to 13 mm as follows:

Stiffness_((actual width))=[Stiffness_((13 mm))/13 mm]×actual width (mm)

peak bending force_((actual width))=[peak bending force_((13 mm))/13mm]×actual width (mm)

Report peak bending force to the nearest 0.1 N and the Stiffness to theNearest 0.1 N/m.

Extensibility Test

Extensibility of the fastening member is measured using a constant rateof extension tensile tester with computer interface (a suitableinstrument is a MTS Alliance under TestWorks 4 software, as availablefrom MTS Systems Corp., Eden Prairie, Minn.) fitted with a suitable loadcell. The load cell should be selected to operated with 10% and 90% ofits stated maximum load. All testing is performed in a conditioned roommaintained at about 23 C±2 C and about 50%±2% relative humidity. Herein,width and length of the specimen are a lateral width and longitudinallength as defined herein. Precondition specimens at about 23 C±2 C andabout 50%±2% relative humidity for 2 hours prior to testing.

Prepare fastening member for testing as follows:

-   -   1. If the fastening member is attached to an article, cut it        free from the article at a location sufficiently inboard of the        junction line that a tensile tester's grip can sufficiently        grasp the specimen for the testing.    -   2. Identify the junction line (51 as described in examples        herein) and mark a line on the fastening member coincident with        the junction line (for example using a fine point pen, such as a        fine point Sharpie).    -   3. Identify the fastening zone inboard extent (88 as described        in examples herein) and mark a line on the fastening member        coincident with the fastening zone inboard extent (for example        using a fine point pen, such as a fine point Sharpie).    -   4. Lay the fastening member on a substantially flat, horizontal        surface and measure width WS as described herein, with no        lateral tension force applied to the fastening member.    -   5. Measure lengths LFP and LEP (as described in examples herein)        to the nearest 1 mm, with a steel ruler traceable to NIST.    -   6. Along fastener zone inboard extent, mark the fastener zone        longitudinal midpoint (measure length LFP (as described in        examples), the midpoint is at ½ of LFP.        Test the specimen:    -   1. Insert the outboard end of the fastening member into the        upper clamp in the tensile tester such that the clamp is        centered in the tensile tester fixture, the clamp width is at        least as wide as the length dimension LFP of the fastening        member, the face of the clamp (once it grips the specimen) is        aligned with the fastener zone inboard extent 88 to within 1 mm,        the longitudinal midpoint of the fastener zone inboard extent 88        is aligned with the center of the clamp, and the unclamped        portion of the fastening member hangs freely downward from the        upper clamp.    -   2. Insert the inner end of the fastening member into the lower        clamp in the tensile tester. The lower clamp width is chosen        such that no portion of the fastening member extends beyond the        width of the clamp. The face of the clamp (once it grips the        specimen) is aligned with the junction line to within 1 mm, and        the specimen is oriented such that if a lateral line were drawn        from the fastener zone longitudinal midpoint, it would extend        vertically and align with the center of the fixture holding the        lower clamp.    -   3. Extend the jaws of the tensile tester such that the distance        between the face of the upper clamp and face of the lower clamp        is equal to WS. Set gage length equal to WS.    -   4. Zero the crosshead location and load.    -   5. Set the tensile tester to extend the specimen at a rate of        254 mm/minute and collect data at a frequency of at least 100        hz.    -   6. Initiate the test such that the tensile tester's clamp        extends the specimen at the defined rate and data is collected        into a data file.

Calculate the Results:

-   -   1. Determine from the data the overall extensibilty under load        at 8N, calculated as

100%×[Distance Extended from Zero-point at 8 N load/WS (at no lateraltension load)].

-   -   2. Determine from the data the extensibility under load per        fastener zone length at 2.1 N/cm-LFP, calculated as

100%×[Distance Extended from Zero-point at 2.1 N/cm-LFP load/WS (at nolateral tension load)],

-   -   -   where 2.1 N/cm-LFP load=2.1 N per centimeter length of LFP,            for example, if LFP is 3 cm, load of 2.1 N/cm-LFP=6.3 N.

    -   3. Determine from the data the extensibility under load per        extensible zone length at 1.0 N/cm-LEP, calculated as

100%×[Distance Extended from Zero-point at 1.0 N/cm-LEP load/WS (at nolateral tension load)],

-   -   -   where 1.0 N/cm-LFP load=1.0 N per centimeter length of LEP,            for example, if LEP is 6 cm, load of 1.0 N/cm-LFP=6.0 N.

Dimension Methods

Various dimensions and ratios thereof are specified herein. Eachdimension is measured according to the following method. All testing isperformed in a conditioned room maintained at about 23 C±2 C and about50%±2% relative humidity. Herein, width and length of the specimen are alateral width and longitudinal length as defined herein. Preconditionspecimens at about 23 C±2 C and about 50%±2% relative humidity for 2hours prior to testing.

Prepare fastening member for testing as follows:

-   -   1. Lay the fastener on a substantially flat, horizontal surface.    -   2. Identify and mark any needed reference lines to enable the        measurement (such as the junction line, L0, L25, L75, L100,        etc.) (for example using a fine point pen, such as a fine point        Sharpie).    -   3. Measure each needed dimension to the nearest 1 mm using a        steel ruler traceable to NIST.    -   4. Calculate any needed ratios as follows: Ratio=100%×[First        Measurement/Second Measurement]. For example, the ratio of the        length of L25 relative to L100=100%×[Length of Line L25/Length        of Line L100].

The dimensions and values disclosed herein are not to be understood asbeing strictly limited to the exact numerical values recited. Instead,unless otherwise specified, each such dimension is intended to mean boththe recited value and a functionally equivalent range surrounding thatvalue. For example, a dimension disclosed as “40 mm” is intended to mean“about 40 mm”.

All documents cited in the Detailed Description of the Invention are, inrelevant part, incorporated herein by reference; the citation of anydocument is not to be construed as an admission that it is prior artwith respect to the present invention. To the extent that any meaning ordefinition of a term in this written document conflicts with any meaningor definition of the term in a document incorporated by reference, themeaning or definition assigned to the term in this written documentshall govern.

While particular embodiments of the present invention have beenillustrated and described, various other changes and modifications canbe made without departing from the spirit and scope of the invention. Itis therefore intended that the scope of the invention is not limited bythe description above or by the drawings, but rather, only by theappended claims.

1. A wearable article, comprising: an integrally-formed, highly extensible fastening member extending from a junction line, said fastening member extending along a stretch direction transverse to said junction line, and ending at an outboard end, wherein said junction line connects first and second longitudinally outermost junction points on a first longitudinally outermost lateral edge and an opposing second longitudinally outermost lateral edge, respectively, said first longitudinally outermost lateral edge having a first profile beginning at said junction line and ending at said outboard end, and said second longitudinally outermost lateral edge having a second profile beginning at said junction line and ending at said outboard end; an extensible zone bounded by inboard and outboard extensible zone extents; and a fastener zone disposed outboard of said extensible zone, said fastener zone comprising a fastener, and having first and second inboard fastener zone corners, said fastener zone having a Stiffness of at least about 1,500 N/m; wherein said fastening member has an acting width (WA) measured from an outboard edge of said fastener zone to said inboard extensible zone extent line; said acting width is bounded by longitudinal lines W0 and W100, and said acting width may be divided into four equal portions by longitudinal lines W25 at 25% of said acting width, W50 at 50% of said acting width, and W75 at 75% of said acting width; and at least one of said longitudinally outermost lateral edges defines an inflection point approximately between lines W25 and W50.
 2. The wearable article of claim 1 wherein said first profile intersects a first line segment connecting said first longitudinally outermost junction point and said first inboard fastener zone corner, at a first intersection point inboard of said first inboard fastener zone corner.
 3. The wearable article of claim 1 wherein said fastening member has an acting width (WA) measured from an outboard edge of said fastener zone to said inboard extensible zone extent; said acting width is bounded by longitudinal lines W0 and W100, and said acting width may be divided into four equal portions by longitudinal lines W25 at 25% of said acting width, W50 at 50% of said acting width, and W75 at 75% of said acting width; said fastening member has lengths L0, L25, L50 and L100 measurable along lines W0, W25, W50, and W100, respectively, and the following relationships exist: L0 is at least about 25% of L100; L25 is at least about 30% of L100; and L50 is at least about 50% of L100.
 4. The wearable article of claim 1 further comprising a strengthened end region disposed outboard of said extensible zone, said strengthened end region having an inboard length (LR); wherein said inboard length (LR) is within the range of about 66% to about 80% of said fastening member length (L).
 5. The wearable article of claim 3 wherein the following relationships exist: L0 falls between about 25% and about 65% of L100; L25 falls between about 30% and about 60% of L100; and L50 falls between about 50% and about 100% of L100. 